As everyone knows, Bach, the doyen of composers, wrote only two Passions, both transcendent masterpieces. Well, it turns out that is not strictly true: he also wrote a lost Mark Passion, a seemingly smaller-scale work, and the libretto by a certain Picander still exists, providing evidence as to the form the missing Passion might have taken. Following familiar Baroque practise Bach would seem to have adapted existing music including the famous Trauer-Ode, BWV198. Other elements are less certain; what is undeniable is that every recreation of the work is at least partly shaped by the views of the artists involved. When a musician of the calibre of Jordì Savall turns his attention to this kind of musical puzzle we can rely on the results being not just intriguing, but superlatively musical.